Telerobotic exploration and development of the Moon

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Telerobotic exploration and development of the Moon
B L Cooper
1,∗
,B Sharpe
2
,D Schrunk
3
and M Thangavelu
4
1
Oceaneering Space Systems,Houston,Texas,USA.
2
Independent Lunar Development Planner,St.Louis,MO,USA.
3
Quality of Laws Institute,Poway,CA,USA.
4
Space Exploration Architectures Concept Synthesis Studio,Division of Astronautics and
Space Technology and School of Architecture,University of Southern California,USA.

e-mail:bcooper138@houston.rr.com
There has been a debate for the last thirty years about the relative merits of human versus robotic
systems and we argue here that both are essential components for successful lunar exploration and
development.We examine the role of robots in the next phases of exploration and human develop-
ment of the Moon.The historical use of robots and humans in exploration is discussed,including
Apollo-era exploration,International Space Station,and deep-water petroleum exploration.The
technological challenges of lunar operations are addressed in the context of how robotic systems
can be designed for robust and flexible operations.Systemdesign recommendations are given based
on the lessons learned from terrestrial and space robotics.
1.Introduction
The Moon is becoming the principal focus of
the space exploration and development efforts of
national space agencies.Following the lunar mis-
sions that are currently in development by many
different countries,an international lunar base is
expected to be established in the next several years.
The first elements of the lunar base will be assem-
bled with robotic precursor missions,and human
missions will follow,perhaps within a decade.
There has been a debate for the last thirty
years about the relative merits of human versus
robotic exploration.Proponents of robotic explo-
ration point out that it’s much less expensive to
send robots into space than it is to send humans,
and that robots,as extensions of our senses,are
our ‘virtual presence’ in the solar system.They
argue that robots can do anything that humans
can do,and they can do it cheaper.On the other
hand,people who worked on the Apollo missions
argue that humans have unique capabilities for
on the spot thinking,observing,and reasoning.
They list examples of how humans can fix things
that break,improvise when plans change,and take
advantage of unexpected opportunities.Most of
this discussion has focused on the ‘either/or’ line of
reasoning.
We argue that the ‘both/and’ approach is more
useful,and we examine the role of robots in the
next phases of exploration and human development
of the Moon.
1.1 Apollo experience
Telerobotic devices were successfully operated on
the lunar surface in the 1960s and 1970s during the
Luna,Surveyor,and Apollo programs.Spacecraft
instruments were commanded mainly in real-time
by operators on Earth,and receipt confirmed in
control areas via the available tools – strip charts,
printouts and still and video images of various
resolutions.
Controlling lunar surface devices was relatively
cheap and simple,compared to other space opera-
tions.The Moon is a cooperative target for earth-
based antennas in terms of its position in the
sky and near-unchanging distance;and pointing
Keywords.Telerobotics;lunar exploration development.
J.Earth Syst.Sci.114,No.6,December 2005,pp.815–822
©
Printed in India.
815
816 B L Cooper et al
antennas on the Moon’s surface back toward Earth
is also relatively simple.The physical environment
is predictable,and in itself contains nothing requi-
ring fast or complicated reactions.Moreover,there
is little to cause hardware deterioration,the main
design considerations being long-term effects of
radiation (including solar flares),meteorites,tem-
perature extremes,and dust.A new generation of
devices could be made to last indefinitely,provided
sufficient safeguards were designed into the hard-
ware and operating procedures.
With today’s available and emerging technolo-
gies,earth-bound operators and audiences could
have a far greater sense of participation.They
could ‘work on the Moon’ every day,and be home
for dinner.
1.2 International space station experience
Currently,the number of space walks needed for
assembly and maintenance of ISS is so large that
there is little time left over for science.Design-
ers did not fully appreciate that the complexity
and newness of the ISS would translate into unex-
pected maintenance.Now,NASA is exploring ways
to use robots that are operated either by the crew
onboard the station,or by ground control person-
nel,for maintenance – so that fewer space walks
will be needed,and more time can be used for
scientific research.
1.3 Deep-ocean experience
In the last 20 years,we have learned that the opti-
mum method of exploring the submarine environ-
ment involves both humans and robots.However,
we do not send robots out to do this work and
keep all the humans in the office.The humans go
out on the ship or platform so they can be close
to the action.That way,they can fix things that
the robots cannot fix,react to surprises,and have
as close a viewpoint as possible to what is going
on.
In deep-sea drilling operations,divers are fre-
quently accompanied by remotely-operated vehi-
cles,whose principal job is to fetch and carry tools,
and provide a view of the operations for the people
at the surface.Note that the petroleum indus-
try is classified as a ‘for profit’ institution – they
aggressively look for the most efficient and eco-
nomical way to do business.The fact that they use
robots is strong evidence for the usefulness of this
technology.
1.4 Latency
Radio signals take about three seconds to make a
round-trip from the Earth to the Moon and back.
This amount of time lag,called latency,is the
time it takes an earth-bound operator to experi-
ence the results of an action.In highly dynamic
situations such as driving a vehicle at apprecia-
ble speed,latency would be a problem,and an
operator could quickly find himself in a disorient-
ing situation,potentially damaging to the equip-
ment or work.There are two ways of handling
the latency problem:first,proceed slowly;and sec-
ond,use automated subroutines (as discussed in
section 2.1b).
2.Technological challenges
2.1a Go slowly
Going slowly means designing operations so that
the situation does not get ahead of the operator’s
ability to control it.On the Moon there is nothing
in the natural environment that will require fast
response to an unanticipated event.Quick reac-
tions would only be required in contingency situ-
ations if something unexpected happened,and
keeping a slow pace will reduce the chances of those
occurrences.
Going slowly has other benefits.In the case
of mobility devices,less lunar dust (a nemesis of
thermal control) will be disturbed and redeposited
where it is not wanted.Going slowly requires less
bandwidth for control and uses less energy for
mobility – and it lessens the harmful side effects
from dissipating the heat that would otherwise
be caused by expending energy for speed.In the
Moon’s vacuum,the only practical way to get rid
of excess heat is by radiation.The only downside to
working slowly may be a human one,i.e.,impa-
tience with a scheme of things that does not match
the way things would be done on Earth.Slow-paced
lunar operations might not only be found boring
to watch,but there could be a tendency to think
of them as inefficient,i.e.,not getting things done
‘fast enough’.
2.1b Automated subroutines
A second kind of lunar tele-operation will involve
controlling devices that replicate the hand-eye
coordination of a skilled technician.This is the kind
of situation presently associated with surgical
telemedicine.Two manipulators for hands,and two
cameras for stereovision to an operator,along with
some upper-body mobility,would be ideal.It will
be useful to include processors and software in the
lunar equipment that could control specific pre-
cise or repetitious operations,so that the role of
the earth operator would be more supervisory.This
method would be similar to the way many factory
Telerobotic exploration of the Moon 817
robot devices work on Earth.The control soft-
ware would be fine-tuned and updated from time
to time.
2.2 Bandwidth requirements
Sensory immersion in operator control stations
requires high-bandwidth,high-resolution systems
with stereo audio,imaging,and haptic (tactile)
control (with or without feedback).Higher band-
width does not eliminate the latency problem,but
would provide more information that could be used
for making better decisions.Device control as well
as video and data could be stored as multi-channel
records,which would later be used for analysis,
training,and general distribution.
2.3 Infrastructure requirements
Initially,a facility to control lunar devices might
resemble previous control centers.There would be
command and display equipment for operators,as
well as a network of computers,data lines,and
transmitter-receiver stations at various places on
Earth.Safeguards for both physical security from
outside,and prevention of operator errors before
they are made (via simulation and command-
checking) would be included.
Some work stations for operator control of
devices (both ‘mobility’ and ‘skilled technician’
types) would be present,to provide a virtual lunar
environment for some of the operators.This sense
of being on the Moon could be distributed to
the outside world via a virtual viewing-room envi-
ronment for observers,with media feeds to the
world at large.A control architecture would be
chosen which would allow for eventual unlimited
expansion of the numbers of devices on the lunar
surface.
A long-term goal would be to distribute the
tele-operation command capability to outside loca-
tions:corporations,universities,and individuals.
Groups and individuals could then be assigned
time slots to be on the Moon in a virtual sense,
conducting activities of their own design for their
own purposes.
2.3a Lunar base requirements
An essential requirement for tele-operations of
robotic devices on the lunar surface is line-of-sight
communications that enable earth-bound opera-
tors to have a virtual presence on the Moon,and
long periods of sunlight to provide power for solar
cells.Sharpe and Schrunk (2002) present a ratio-
nale for why the summit of Malapert Mountain,
in the south polar region of the Moon,offers the
1
Funded by NASA Johnson Space Center’s Automation,Robotics,and Simulation Division.
optimumlocation for direct and continuous Earth–
Moon communications and long periods of con-
tinuous sunlight.Other sites that experience long
periods of sunlight,such as Peary Crater at the
North Pole and Shackleton Crater at the South
Pole,are not continuously in line-of-sight with
the Earth.For Earth–Moon communications,these
polar sites would need to have a relay station
placed on the lunar surface or in lunar orbit,which
would add significantly to the cost and complexity
of robotics operations.Thus,for the first robotic
lander missions to the Moon,Malapert Mountain
should be given consideration as the location of the
first sunlight-dependent robotic base (Sharpe et al
2003).
3.The robot associate study
We performed a study recently
1
to determine the
most efficient and important ways to use robots in
future lunar exploration.We found that there are
specific,relatively easy,and very useful things that
we can do with robots.
First we looked at tasks that would be best
suited to robots in future space missions.Next,
we prioritized the list of tasks,to understand
which capabilities would offer the greatest return
on investment.We wanted to find out which tasks
would be easiest to develop into robotic tasks,while
at the same time being the most beneficial for the
mission.
3.1 Study background
Once we are on the surface of the Moon,you face
a new set of challenges that are distinctly differ-
ent from spacewalking on orbit.You have a partial
gravity environment.Now,instead of just adding
inertia,your space suit weighs something,and you
have to deal with that weight as you move around.
Also,you now have a sense of up and down.You
can not change your orientation randomly to pick
something up.If there is a rock on the ground that
you want to look at,you must bend down to get
it.You now have to worry about keeping your bal-
ance.We learned fromApollo that this can be very
challenging in a 200-pound space suit.And because
the gravity on the Moon is less than the gravity
on Earth,you have problems that you would not
encounter on Earth – such as the cables they used
to deploy the Apollo surface experiments:there was
not quite enough gravity to keep them flat,so they
were a constant tripping hazard.
There are tasks which could be done robotically
that would make spacewalks or planetary excur-
sions more productive or easier.These ‘Assistance’
818 B L Cooper et al
tasks are fairly well understood because of our
experience with robots in industry.
Exploration and development of the Moon will
also involve robotic precursor missions that will
arrive a couple of years ahead of the humans,
prepare the base site,set up the modules,get the
oxygen plant running,get the power plant running,
and so on.Then the challenge is to keep everything
running until the humans arrive.But if we want to
send humans to the Moon,these robotic capabili-
ties must be developed.
3.2 Methodology
A list of potential tasks for robotic automation or
tele-operation was created.We then set up criteria
to determine which tasks are both easy to roboti-
cize and,at the same time,most beneficial.Each
task was given a grade for aspects of difficulty and
benefits,and the difficulty/benefit scores were tab-
ulated.The goal was to find the tasks that are easy
for robots to do (low scores on the difficulty scale)
and tasks that are beneficial for robots to do (high
scores on the benefit scale).
3.2a Difficulty aspects
Technical risk
For some tasks,such as inspection of a vehicle
exterior,there are systems that are already space-
proven.The technical risk is thus low.For other
systems,such as emplacing a lunar surface habi-
tat,the hardware is all in the artwork phase.The
technical risk here is comparatively high.
Complexity of the task
Some tasks are simple – they only require one or
two steps;there may be only one or two objects to
be manipulated,and the robot would not have to
be very dexterous to do them.Obviously other
tasks are more complicated,and simple tasks are
easier to roboticize than complex ones.
Robotic compatibility
This is the general question of how well could
robots (as we understand them) do this task?For
example,inspecting debris shields for micromete-
oroid damage is very compatible with robotics,
whereas repairing those shields is not.On a plan-
etary surface mission,observing a sample with a
microscope is a robot-compatible task,but deci-
ding which sample should be placed under the
microscope is not robot compatible.
It is hard to put a metric on the robotic compati-
bility factor.Instead,we showed our list of tasks
to a group of robotics experts,and asked them to
give us their opinions on which tasks are,or are
not,robot-compatible.It is important to note that
robot-compatibility can be built into a design,if
you plan it that way ahead of time.So for many of
the planetary surface tasks,we can only say that
the task could be robot-compatible,if the designers
decide to make it so.
Task criticality
What are the consequences of a failure of the robot
to accomplish the task?If it is just a minor incon-
venience,then you do not have to design in as much
redundancy as you would if the failure would lead
to a catastrophe.
3.2b Benefit aspects
Task duration
How much spacewalking or surface excursion time
might be saved if a robot could do the task?
Task frequency
How often would that block of time be saved?If
the task requires five hours,but only happens once
during the whole mission,then maybe that is not
the most beneficial way to use robots.Instead per-
haps,we should pay attention to tasks that require
an hour every day.
Task pervasiveness
If a task is performed at lots of different places,it
probably is more beneficial to roboticize it.
Human factors
Something that the crew would consider as chal-
lenging,interesting and fun would not be as bene-
ficial to roboticize as something that was tedious,
boring,strenuous,or dangerous.
Distance from safety
Finally,how far away fromthe airlock is the human
going to be if they perform this task?If they are
very close to the airlock,then they spent less time
getting to the work site,and it is quicker to get
back to the airlock in an emergency.All other
things being equal,it would be more beneficial to
roboticize tasks that take place farther from the
airlock.
For planetary surface missions,we identified a
larger number of tasks that would be associated
with surface excursions,because surface traverses
by humans would be a primary science activity.
Telerobotic exploration of the Moon 819
Figure 1.Payback for robotic tasks that occur in conjunction with human activity.Lower ‘difficulty’ numbers and higher
‘benefit’ numbers represent the most useful robotic tasks for early development.Complete list of tasks (represented here by
numbers only) may be found in Cooper and O’Donnel (1999).
Figure 2.Payback for long-term enabling technology tasks.Robot development should focus on the low-difficulty,high-
payback tasks in the upper left quadrant.
3.3 Results
The highest-payback tasks for the ‘Robot Assis-
tant’ are shown in the upper left quadrant of
figure 1 – least difficulty,greatest benefit.For
example,scooping,grasping and raking scores well
as a task that would give a high payback for robot-
ics development.Breaking rocks,observing themin
the field with a microscope,and autonomous sur-
face traverses also got high marks.By comparison,
loading samples into a return spacecraft was not
very useful.
Enabling technology for planetary surface mis-
sion phases includes some rather daunting tasks,
and,as we mentioned before,the question to be
asked is not whether it makes sense for a robot to
do these things instead of a human.There are no
humans in the scenario.So how do we score them
with respect to benefit?It may be useful to ask
ourselves a slightly different question:Which tasks
should be roboticized,which tasks should be devel-
oped for hard-automation,and which tasks should
not be considered for now?
Because these are enabling technologies for
future human missions to the Moon,we do have
to consider them,but it is nevertheless useful to
know that trenching and excavating is a higher-
payoff task than landing site survey and certifi-
cation.From the standpoint of efficient allocation
of resources,the high-benefit tasks should be
820 B L Cooper et al
addressed first.Technologies developed and lessons
learned can then be applied to the more difficult,
or possibly less beneficial,tasks (figure 2).
3.3a Pervasive subtasks
Closeout images
There was a third category of tasks that we call
‘pervasive subtasks’ (figure 3) that have to occur
in just about any robotic mission.For example,
when a repair is completed,it is very important
to take some pictures of the completed job.These
are typically referred to as ‘close-out’ images.They
allow you to take a careful look at your work after
you get back inside,and then,in a leisurely fashion,
you can decide if the job was done well enough,or
if instead you need to plan another spacewalk to
go out and fix it again.
Situational awareness
Another important ‘pervasive subtask’ is situa-
tional awareness.An astronaut working in a space-
suit has limited vision and limited range of motion,
and it is very easy to bump into or get snagged on
something.That is one of the reasons that at least
two people should go out on each spacewalk – to
have a buddy there in case of trouble.So,having a
robot that can just watch out for problems (being
managed perhaps by a human who is just inside)
can be a very useful option.
Imagery
We have seen that the capability of taking still
or live imagery is important in many of the high-
payback tasks.This makes sense,if you consider
the fact that you need to be able to see what you
are doing,whether you are a robot or a human.
And if you are a robot,you probably need visual
information to a greater extent,because you lack
the sense of touch feedback that a human has.
When astronauts are performing maintenance
during a spacewalk,having a camera on the end
of a manipulator would allow them to peek around
corners or under things.A flying eyeball for inspec-
tion of the exterior surface of the spacecraft helps
identify problems,assess work sites,find leaks,
and in general allows better planning before the
spacewalk begins.On a planetary surface,having
a camera on the end of a manipulator might allow
the crew to choose samples for inspection,without
having to pick them all up,just to throw most of
them back down.
This imagery capability is also central to landing
site survey and qualification – it is useful to see
what is there in detail so that you can plan ahead
for challenges,or you may decide to pick another
location for your initial base camp.These tasks
involve mobility and the ability to capture images.
Since they do not involve manipulating objects,
they are generally the easiest things to do with
robots.
Mobility and manipulation
Some tasks involve manipulation in addition to
mobility.Among these,the highest-payback tasks
involve maintenance.When we begin designing
the systems that will allow humans to live on
the Moon,we should remember to add robotic
interfaces to things that could break,and to
include robotic compatibility in the design.Things
that are robotically compatible should be human-
compatible as well,because that adds redundancy
to the design.
Lessons learned
We need to plan ahead intelligently to use robots
as efficiently as possible.We have learned a few
lessons from international space station and from
terrestrial robotics applications,about what works
and what does not work so well.Here is our short
list of those lessons learned.
• Successful work systems rarely double as techno-
logy demonstrations.Usually,the prototype is a
way to learn how to do things better,and we do
not expect that prototype to stay on the job for
years.We need to understand the robotic sys-
tem and have some operational experience with
it,then develop the ‘workhorse’ based on that
experience.
• Design tasks for single-arm operations.In space,
you need to hold on to whatever you are working
on.On a low-gravity planet,you may need to
hold onto something to keep your balance.The
robot will probably require the same thing,and
the object is to make the task operable by either
human or robot.
• Minimize fasteners and actuators.Find a way to
use only two bolts instead of twenty.Only one
switch instead of ten,and so forth.
• Provide clear visual and physical access and
visual cues and design those visual cues with the
imaging system in mind.In other words,do not
make an orange-and-white target for a mono-
chrome (black-and-white) visual system.
• Minimize motion requirements.If you need to
turn a valve,build a tool with a motor in it,
instead of a steering wheel or lever.
• Provide alignment guides.Make sure that the
alignment guides are located where the vision
system can see them.
• Allow for proper tolerances between parts – there
is a balance between too tight a tolerance and
Telerobotic exploration of the Moon 821
Figure 3.Pervasive subtasks,activities and capabilities.These items are candidates for automated subroutines (other
candidates are discussed in section 2.1.2).
Figure 4.The microconical tool,developed by Oceaneering Space Systems in support of the International Space Station
(ISS).
too loose a tolerance,and either one can cause
problems.
• Provide status indicators for robot-activated
functions.Robots usually have no tactile feed-
back system,so they need some way of knowing
when they have made the connection,tightened
the bolt enough,and so on.
• Provide clear identification of objects and direc-
tions.UP and DOWN do not apply if you do not
have a neurovestibular system.
• Provide operational margins – design for the mid
range of capabilities.You may expect a mecha-
nism to work continuously for fifteen years,but
you should make it easy to replace anyway.
• Limit the amount of force required to operate
mechanisms.That makes it more human-
compatible,and more robot-compatible at the
same time.
3.4 Recommendations
3.4a RoboTractor
The development of a robotic excavation/soil-
moving capability is a critical component of an
overall robotic exploration system.
3.4b Engineering standards
Equipment for lunar development should be
designed with open-ended operations in mind –
no more ‘missions’ that have a defined end-point.
Design consideration must be given to commona-
lity standards so that every piece of equipment sent
to the Moon now and in the future can be inter-
faced (added to or cannibalized/reconfigured) with
all other equipment.
3.4c Incorporate a telerobotic control mode
Incorporate a limited tele-operation control mode
(where feasible) to robotic systems to permit them
to be ‘driven out’ of situations where supervisory
or autonomous control technologies may not be
adequate.
3.4d Design early for robots
Make provisions to include robot capabilities as
part of the overall planetary work system early in
the planning stages of future missions.Incorporate
robot-specific interfaces so that tasks can migrate
to robotics as the capabilities are fielded.Figure 4
shows a device called the micro-conical tool.It is
822 B L Cooper et al
used on the Space Station as an attachment device.
It was designed to be operated either by a human
or a robot – even though we do not have robots
on Space Station yet that can actually use this.
When a human uses it,the ‘steering-wheel’ device
on the left is hooked up to the microconical,and
the human can easily turn it.When a robot is work-
ing,the robot uses the rotating tool shown on the
right.
3.4e Develop robot surrogate capabilities
Continue to develop robot surrogate-type capabil-
ities.These options provide a unique capability to
flexibly respond to contingency and emergency sit-
uations when suited human crew members are not
available.
3.4f Plan ahead
Identify overhead tasks associated with the pri-
mary job so that time lines accurately reflect the
required work.When a more accurate timeline
is established the need for robot capabilities and
interfaces becomes apparent.When the need is
defined,a more efficient system (combining human
and robotic tasks) can be developed within a con-
text that best supports the overall mission.
Historically,a lack of understanding of what kind
of work robots could actually perform in space led
to a reluctance to place them in the critical path
of assembly or maintenance activities.Therefore,
robotic accommodations were not widely incorpo-
rated into the architecture due to cost,weight,vol-
ume,etc.As development continued and new tasks
were discovered,it was difficult and even more
expensive to retrofit the space hardware for robotic
operations.
3.4g Build a little,test a little
Provide robot demonstrations early in the plan-
ning stages of a mission to instill confidence and
to showcase capabilities to mission planners and
managers.Robot accommodations and tasking will
occur when planners and managers understand
what robots can do and what is required (accom-
modations) for them to perform the tasks.
3.4h Mobility is key
Mobility is an enabling robot capability.Almost all
tasks examined for robots include a requirement
for this capability.Technologies that implement or
facilitate robot mobility are critical to future plan-
etary exploration.
4.Conclusions
Telerobotic technologies are beneficial to future
lunar development,and should be incrementally
developed by starting with those tasks which are
the most beneficial and the least difficult to roboti-
cize.When these technologies are proven (albeit at
the microscopic/microwatt level),they will signal
the beginning of the true ‘space age’ – large-scale
space operations comprised of a mix of human,tele-
operated,and autonomous robotic participants.
Acknowledgements
This work was funded in part by NASA Johnson
Space Center and Oceaneering Space Systems,
Houston.
References
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unpublished white paper presented to NASA Johnson
Space Center Automation,Robotics,and Simulation
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to the Moon;Presented at the World Space Congress,
CoSpar Session,Houston,Texas.
Sharpe B,Schrunk D and Thangavelu M 2003 Lunar Ref-
erence Mission:Malapert Station;Proceedings of the
International Lunar Conference 2003 (ILEWG-5),Kohala
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